PKS 1127-145 Absorber
Illustration
On their way to Earth, the X-rays from PKS 1127-145
pass through a galaxy located about 4 billion light
years from Earth. Atoms of various elements in this
galaxy absorb some of the X-rays. By measuring the
amount of absorption, astronomers were able to estimate
that the intervening galaxy contained only about 20
percent as much oxygen as our Milky Way Galaxy has
now.(Credit: NASA/CXC/M.Weiss)

X-ray and Optical, Side by
Side
This composite shows the same field of view in the
optical (left) and the X-ray (right) observed with
Hubble and Chandra respectively.(Credit: X-ray:
NASA/CXC/A.Siemiginowska (CfA) & J.Bechtold (U.
Arizona) Optical: NASA/HST/CfA/A.Siemiginowska et
al.)